While many Arsenal fans will have been breathing a sigh of relief after their indifferent start to the season, bottom-of-the table West Ham and boss Manuel Pellegrini are still searching for their first points.
Aaron Ramsey nodded in the rebound but was flagged offside, before West Ham broke and Arnautovic arrowed an effort into the side-netting.
"No problem with the player". More transition. For the second half we were speaking in the dressing room and to help more inside with two midfielders.
Premier League quiz: Can you name top 21 French goalscorers?
While City backed the introduction of VAR, it requires at least 14 of the 20 clubs to approve any changes in the Premier League. It could so easily have been all three points with Sergio Aguero (twice) and Raheem Sterling all hitting the woodwork.
Neither side could carve out another clear-cut chance as the half went on, as they went into the halftime break level pegging.
Matteo Guendouzi was robbed of possession by Anderson, who broke forward and crossed for Arnautovic but he could not make telling contact and Cech saved easily.
Substitute Danny Welbeck sealed the victory in stoppage time, when Bellerin found him unmarked in the area. "We need to add points, but we are going to continue searching".
Details of the illness were not disclosed by the club as the former German global sat out the Gunners third league game of the season.
Liverpool top after Salah goal sinks Brighton
The visitors did come out brighter in the second half, but they were still unable to carve out clear-cut chances. Hughton was pleased with his side's response to going a goal down at Anfield.
"I think they all know we are making too many changes and in the first three games, we haven't had the results that we wanted, but in every game we are improving".
Arsenal's pressure was rewarded in the 70th minute when Lacazette controlled well on his chest and swivelled for a shot that cannoned off Diop and into his own net.
But Arsenal's inconsistent performance suggests Emery still has much to work on as the Spaniard aims to restore his new club to the top four after last season's sixth-place finish.
It was just the bit of luck that Emery was searching for as Arsenal struggled to control the game for long stretches.
Jose Mourinho tells Manchester United to cut out mistakes: 'Nobody is happy'
After the defeat to Brighton Pogba admitted United had the wrong attitude and said he was at fault as much as anyone. Decisions to be made on Sunday but yes they are training with the team", the Portuguese explained.